A microchannel heat exchanger (MCHX) includes heat exchange tubes with a flattened surface that extend between two headers. Refrigerant flows through the heat exchange tubes and exchanges heat with air that flows over the heat exchange tubes. A folded fin including a plurality of fin plates can be located between two adjacent heat exchange tubes. Each fin plate is connected to an adjacent fin plate with a curved portion. Each fin plate includes louvers to create turbulence in the airflow and enhance heat transfer between the refrigerant and the air. The louvers have a length extending between the heat exchange tubes.
Due to the higher surface density, condensation and frost can form in the microchannel heat exchanger. Any condensate that forms can flow along the surface of the fin in a serpentine path towards the bottom of the fin. However, the condensate can build up in the curved portions near the heat exchange tubes where it is coldest and form frost.
FIG. 1 illustrates a prior art fin plate 100 including a plurality of louvers 102 each separated by a gap 104. An entirety of each louver 102 is located in a single plane.
In one prior heat exchanger described in U.S. Pat. No. 4,676,304, some of the louvers of a fin plate are angled downwardly with respect to a body of the fin plate, and other louvers of the fin plate are recessed and located below and parallel to the body of the fin plate. The angled louvers are located in one portion of the fin plate, and the recessed louvers are located in another portion of the fin plate.
In another prior heat exchanger described in Japanese Publication No. JP56157793, a crest portion is located in a middle of the length of each louver, the crest portion being higher than ends of the louver. Any condensate that forms on the fins is directed towards the lower ends of the louver and near the heat exchange tubes for draining.